1. Field of the Invention
The present invention relates to the technical field of a room mirror for cars, and more specifically, to a room mirror having a display module.
2. Description of the Related Arts
In general, various audiovisual alarm devices are installed in cars as a means for safe driving. However, an alarm device for giving information on a dangerous situation of the rear area of a car which is beyond a driver's visual field is hardly installed. Mirrors are attached to various places of the inside and the outside of the car so that the driver can directly look a situation of the rear area of the car.
These mirrors are divided into a side mirror which is installed in a side door so as to observe the rear area of a car, and a room mirror which is installed in the front glass of a car interior so as to observe front and rear areas of the car.
Thanks to these mirrors, the driver can grasp a rear situation to a certain level. However, because an area in which the rear situation cannot be recognized, namely, a blind spot, which is not shown by the mirrors, may be generated, in a case where an obstacle is located in the blind spot, the obstacle collides with the car, thereby causing a safety accident.
Accordingly, a device which generates warning sounds to call the driver's attention when a car comes close to the obstacle has been recently provided. Thus, when the car comes close to the obstacle, the obstacle warning device for giving the driver information on situation has been installed so that a collision of the car and the backward obstacle can be inhibited in advance. Additionally, like a display room mirror as disclosed in Korean Registration Utility Model No. 20-0264726, by installing a monitor, which outputs an image signal so that the driver can confirm a rear image filmed by installing a rear surveillance camera in the car, in a room mirror, when the driver reverses or parks the car, the driver can exactly grasp a rear situation for providing safety.
FIG. 1 schematically illustrates the aforesaid conventional display room mirror.
Referring to FIG. 1, a conventional display room mirror 1 is composed of a room mirror 10, a display module 20 installed on a rear surface of the room mirror 10, and a fixing member 30 for fixing the display room mirror 1 to a front glass of a car as illustrated in (a) of FIG. 1. In the display room mirror 1, because the display module 20 should be located in the inside of the room mirror 10, the display module 20 needs luminance of more than 50 times compared to a general display module. Thus, a direct type backlight unit is used therefor.
More specifically, referring to (b) of FIG. 1, the conventional display module 20 has light emitting units 21 formed on a substrate 23, a light guide plate 25 formed on the light emitting units 21 and an optical sheet 27, and thus is composed in a structure which supplies light generated from the light emitting unit 21 to a liquid crystal display panel 29. However, in the conventional display module 20, a total optical gap H1 of the backlight unit is thickened due to a thickness H2 of the light guide plate 25 itself and a thickness H3 of an air gap formed in an upper part of the light guide plate 25. Thus, upon housing of the room mirror, it occupies much inner space. As a result, it is problematic that a total thickness ((a) of FIG. 1, W1) of the display room mirror 1 is thickened, and when mounting a high output light emitting diode, the total optical gap is thickened, and that a degree of freedom in design is reduced according to an increase in the total thickness.